/**
 * @param {string} sentence
 * @return {boolean}
*/
var checkIfPangram = function(sentence) {
  let set = new Set();
  for(let i = 0; i < sentence.length; i++) {
    set.add(sentence[i]);
  }
  return set.size == 26;
};
let sentence = "thequickbrownfoxjumpsoverthelazydog";
console.log(checkIfPangram(sentence));
sentence = "leetcode";
console.log(checkIfPangram(sentence));
